Red eyes after waking up may be caused by overuse of eyes, conjunctivitis, subconjunctival hemorrhage and so on. 1. Excessive eye use: when the eyes are used for a long time, such as the use of electronic products, stay up late, the eyes rest time is reduced, can lead to the phenomenon of waking up with red eyes, and may be accompanied by eye soreness, headache and other symptoms. 2. Conjunctivitis: Conjunctivitis can be characterized by conjunctival congestion, which is manifested by redness of the eyes or increased eye discharge. 3. Subconjunctival hemorrhage: subconjunctival hemorrhage can be triggered by the rupture of blood vessels under the bulbar conjunctiva or the increase of permeability, which is manifested as redness of the eyes. In addition, there are other reasons for waking up with red eyes, the emergence of discomfort and timely consultation, after clarifying the cause of the disease under the guidance of a professional doctor for treatment.